Tanged, perforated metallic core based gaskets for automotive engine usage and the like have been in vogue for many, many years. Frequently such gaskets comprise a central metallic core with facing layers of fiber-elastomer sheets combined with the core via clinching tangs struck from the core to project outwardly from the core so that the metallic core and facing layers may readily be combined and secured.
In some cases such gaskets comprise a tanged core with a facing layer clinched to one face only. In such instances, the surface of the perforated core opposite the surface to which the facing layer is clinched is frequently treated and coated with a variety of materials for different purposes. One such class of materials comprises elastomeric, or rubber-like materials. However difficulties are encountered in providing fully effective elastomeric coatings. For example, many high-temperature elastomers require high curing temperatures, temperatures which sometimes exceed the temperature tolerance of the elastomer in the fiber-elastomer facings. That circumstance eliminates the possibility of using a number of highly desirable elastomeric coatings.
Further, depending on the combining process used and the sealing load between the surfaces to be sealed, the tangs themselves are sometimes subjected to deleterious corrosive conditions in use. Post coating of a combined tanged core and facing layer does not permit coating of the portions of the tangs projecting into the facing layer and certainly does not permit coating of the surfaces of the core or the surfaces of the tangs on the side to which the facing layer is clinched.
It would be desirable, therefore, to provide an improved metallic core-clinched gasket which is suitably coated to enhance the sealing characteristics thereof.